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l Letters Patent No. 76,643, dated April 14, 1868.

IMPROVEMENT IN PUMP-PISTONS.

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` To ALL wHoM I'i MAY coNoERN;

Be it kno-wn that I, SYLVESTER G. MASON, of Rochester, in the county of Monroe, and State of New York,. have invented a certain new-and useful Improvement in Pump-Pistons; and I do hereby declare that the fol lowing is a full and exact-description thereof, reference being had to the accompanying drawings, making part: of this specification. Y, Figure I is a section of a. doubleseting pump-cylinder, and an elevation of my improved pistou situate therein.

Figure 2, a central vertical section ofthe piston. v v Figure 3, an elevation of' the pistou with the valves and enclosing packing-rings removed.

Figure 4, a perspective view ofthe piston shell as arranged in the position for planing the seats for the valves.

Figure 5, a perspective view of one of the packing-rings and valves.

Like letters of reference indicate corresponding parts in all the figures.

My improved piston is of that kind used in double-acting pumps, where the water passes alternately through the top and bottom ofthe piston, and is elevated through a hollow `pistonrod.-

The invention consists in the construction of the shell oi' the piston, with openings made in the sides, said openings being cast in segmental form, so that by simply placing the said shells in a row upon a planing-bed, and running the planing-cutter through, they are properly dressed for the reception Vof the valves.

It also consists, inA combination with such openings, and the valves located therein, of segmentalfpackingrings in the rim ofthe shell, closing the sides, to hold the valves, and expanding by pressure of the water, to pack the piston. V 5

In the drawings, iA indicates the piston-shel1, and B the hollow piston-rod screwing therein. vThe piston-shellV is cast in a single piece', with ,cross-webs, a a, and with vertical connections, 6 b, on opposite sides, which Vthus form openings, c c, for the reception of the valves. This construction divides the pistonl in two halves, except the connection b. The edges, b b', of theseconnections, standing on a plane from side to lside of the shell, enable the cast pistons to be set,`one after another, on the bed of a planing-machine, andthe planing-knife cutting through, dresses the edges or seats al d, against which the valves strike so truly -as to produceja per-,- fect t. l i

A piston-shell is already known, (Patent No. 67,291,) in which openings corresponding to c c are made through the rim,` with a singlevalve restingV therein, and extending through the piston. But, in such case, the said openings are notsegmental, or, in other words," are not carried round to such an extent as to lbring the edgesbb of connections 6 on a line-with each other, and therefore the openings c c cannot be planedout, as I have above described. In such case, the openings being narrow, and not segmental, the only way of dressing or smoothing is by running a iilc through, which renders the seats imperfect and irregular. By casting said openings segmental, and extending them lround and planing through, I can make them perfect, while less material and less'labor are involved. v

The periphery ofthe piston-shell `is dressedin a lathe in the usual manner.

p The valves Gr Gare simply plain segmental leaves, as shown, placed in the'side-openings c c, the ends resting against the edges b bfas guides, and the dat surface striking alternately the seats d d, according as the piston'is worked up or down.

Thepeipliery of the vpiston is formed with a depression or' groove, le, corresponding'in size and position with the openings c, and extending all the way round. In` this groove fit two segmental rings, H H, joining together perfectly iu an angular manner, as shown at z'. .These rings cover the openings und enclose the ,valves in place, so that theycannot. escapeor bind. v

The rings `serve-the treble purpose of enclosing and retaining the valves, of expanding against the cylinder .to produce a packing, and of closing the openings' againstthe outside pressure of'water in the piston, which would otherwise escape outward.' This eect is of much importance ,in connection with the open-sided piston,

for when the rim wears, the openings in the side leave an open escape-passage, which renders the piston in effestive. By the use of the packing-rings, the openings are not only stopped, butthe wear ofthe piston is compensated for by expansion.

I do notclaim simply and bron the same is notnew; but

What I ola-im as my invention, and desire to secure by Letters Patent, is- The combination of the segmental openings c c, formed as above described, and the vulves G G, resting in said openings, with thesegmentalpeeking-rings H H, so arrzinged as to enclose said vuivesfand to act as packings, and retain the Water in the piston, es herein set forth.

In witness whereof, I have hereunto signed my name in the presence oft diy openings in the side of the piston to admit the v'aives, :is I ani' aware Wo subscribing witn esses.

SYLVESTER G. MASON.

Witnesses:

J. A. DAVIS, R. F. Oseoon. 

